Lightning strikes have been observed near Alexandra, as Otago residents are being cautioned to prepare for a second wave of "severe" thunderstorms this evening.
MetService reported lightning in the Central Otago town this afternoon, alongside rain across the South Island.
It comes as Otago residents were advised to avoid travel during thunderstorms and stay away from creeks and rivers.
Severe thunderstorm warnings were in place for Dunedin and coastal areas, as well as North Otago and Central Otago from 2pm until 9pm.
MetService tonight reported severe thunderstorms near Mount Studholme and the Hunter Hills, in South Canterbury, at 6.52pm.
By 7.40pm the severe thunderstorm warning had been lifted from the Canterbury radar area. However, it remained in place for the Canterbury Plains and Canterbury High Country.
The storms were moving southeast and were reported near Fairlie, Burke Pass and Albury at 7.45pm.
The Otago Regional Council has cautioned people in the region as further severe localised downpours and large hail stones have been forecast.
The ORC warned both rural and urban residents to watch out for rising rivers and streams, potential road flooding, landslips and to consider safeguarding stock.
It could create potentially dangerous conditions and possible closures on the road, it said.
That prompted both the ORC and Emergency Management Otago to warn against travel during the thunderstorms.
The warning comes as the clean-up continues from last night's thunderstorms.
It had issued a severe thunderstorm watch for Dunedin, coastal areas, Central Otago and North Otago for today.
ORC Manager Natural Hazards Dr Jean-Luc Payan said thunderstorms can produce heavy localised rain, and today's storms were expected to generate downpours of between 10 and 25mm per hour.
There was a risk those could become "severe", at 25 to 35mm per hour, and produce large hail stones.
Otago Civil Defence and Emergency Management had also shared a 'severe thunderstorm watch' for this afternoon and evening.
"Between 2pm and 9pm, thunderstorms could become SEVERE in Dunedin, eastern Central Otago, North Otago, and the Canterbury Plains and foothills from around Ashburton southwards.
"Severe storms will generate localised downpours with rainfall rates of 25 to 35 mm per hour, and large hail (greater than 20 mm diameter)."
Rainfall of this intensity could cause surface and/or flash flooding, especially about low-lying areas such as streams, rivers or narrow valleys, and may also lead to slips, the warning said.
'Unlike anything we have seen before'
David Robertson, who lives near Beaumont, said a small creek topped its banks in the storm and nearly took out his mailbox in last night's storm.
He believed more than 70mm of rain fell in 30 minutes.
It was "very loud, continuous thunder and lightning, huge hailstones and overflowing spoutings. [It was] unlike anything we have seen before", he said yesterday.
The creek had nearly dried up before last night’s downpour, he said.
"We were actually going to check our shop in Lawrence, but would have needed a boat. No way we were going to safely make it down tonight."
In a video he took of the storm, he describes the hail as "absolutely nuts" before exclaiming: "Look at the size of that hail!".
Roads affected, more thunderstorms forecast
Police said there had been extensive surface flooding on State Highway 8 between Millers Flat and Raes Junction and they closed the road between Raes Junction and Lawrence.
Motorists were asked to take alternative routes or delay their travel.
A spokeswoman for the Clutha District Council said this morning that Rongahere Rd was closed overnight between Beaumont and John O'Groats Rd due to flooding and fallen trees.
The New Zealand Transport Agency advised that SH8 between Millers Flat and Lawrence has been reopened, as has Tima Burn Rd near Millers Flat.
Craig Flat Road at Millers Flat is closed due to a slip.
Surface flooding may be present on roads and motorists were urged drive to the conditions and take care.
The Central Otago District Council placed general flood warnings on Ranfurly and Patearoa community areas due to torrential rain.
It advised caution as the extensive amount of water lifted manhole covers in the streets.
